1. Field of the Invention
The present invention relates to a liquid supply member that supplies liquid to a liquid discharge port that discharges liquid, a method of making a liquid supply member, and a method of making a liquid discharge head.
2. Description of the Related Art
A typical example of a liquid discharge head is an inkjet recording head. An inkjet recording head includes a recording element unit that discharges ink and a tank holder unit that holds an ink tank. The tank holder unit includes a tank holder and a supply path plate.
Ink is guided from an ink tank through a supply path formed in the tank holder unit to the recording element unit and supplied to a discharge port that discharges the ink.
FIG. 9A is a bottom view of a tank holder H1500, and FIG. 9B is a top view of a supply path plate H1600. Opening portions that serve as the supply path are formed in the tank holder H1500 and the supply path plate H1600.
A supply path H1601 is formed by joining the supply path plate H1600 to the tank holder H1500 so that surfaces H1602 having the opening portions face each other. A member having the supply path H1601 is a liquid supply member. The supply path H1601 includes a supply path H1601x through which liquid flows in a direction that intersects the surfaces H1602 having the opening portions and a supply path H1601y through which ink flows in a direction parallel to the surfaces H1602 (FIG. 9B).
Japanese Patent Laid-Open No. 2005-096422 describes a laser welding method that can be used for joining the tank holder H1500 to the supply path plate H1600.
In general, the term “laser welding” refers to a method of joining a member that is transparent to a laser beam and a member that is capable of absorbing a laser beam together by making these members contact each other at a portion to be welded and irradiating the portion to be welded with a laser beam. As compared with ultrasonic welding, laser welding has an advantage in that foreign matter is negligibly generated at the welded portion, and laser welding is used as an effective way of forming a supply path.
Referring to FIGS. 10A through 10C, a method of forming the supply path H1601 by the laser welding described in Japanese Patent Laid-Open No. 2005-096422 will be described. First, the tank holder H1500, which is capable of absorbing a laser beam, and the supply path plate H1600, which is transparent to a laser beam, are made to contact each other using a press jig 510. Subsequently, while the tank holder H1500 and the supply path plate H1600 are in contact with each other, a contact portion 600 is irradiated with a laser beam (FIG. 10A), so that a supply path is formed.
Because the contact portion 600 is disposed so as to form a part of the supply path H1601, after the laser welding, a melted portion W of the contact portion 600 protrudes to the supply path H1601 (FIG. 10C).
FIG. 10C is a sectional view taken along line XC-XC of FIG. 10B. As illustrated in FIG. 10C, if the melted portion W, which is generated by the laser welding, protrudes by a large amount to the supply path H1601x through which ink flows in a direction that intersects the surface H1602, the ink flow may be impeded. In particular, a supply path formed in an inkjet recording head is very small, so that the possibility of such impedance of the ink flow is high, and the performance of ink supply to a discharge head may decrease.